SUBTITLE F: PUBLIC WATER SUPPLIES
CHAPTER I: POLLUTION CONTROL BOARD
PART 611 PRIMARY DRINKING WATER STANDARDS
SECTION 611.TABLE R RADIONUCLIDE CONVERSION FACTORS
Section 611.TABLE R Radionuclide Conversion Factors
Derived Concentrations (pCi•L‑1) of Beta and Photon Emitters in Drinking Water Yielding a Dose of 4 mrem•y‑1 to the Total Body or to Any Critical Organ as Defined in NBS Handbook 69
Conversion Factor
Radionuclide (Isotopic Symbol) (pCi•L‑1/4 mrem•y‑1)
Antimony-122 
90
Antimony-124 
60
Antimony-125 
300
Arsenic-73 
1,000
Arsenic-74 
100
Arsenic-76 
60
Arsenic-77 
200
Barium-131 
600
Barium-140 
90
Berkelium-249 
2,000
Beryllium-7 
6,000
Bismuth-206 
100
Bismuth-207 
200
Bromine-82 
100
Cadmium-109 
600
Cadmium-115 
90
Cadmium-115m 
90
Calcium-45 
10
Calcium-47 
80
Carbon-14 (14C) 
2,000
Cerium-141 
300
Cerium-143 
100
Cerium-144 
30
Cesium-131 
20,000
Cesium-134 
80
Cesium-134m 
20,000
Cesium-135 
900
Cesium-136 
800
Cesium-137 
200
Chlorine-36 
700
Chlorine-38 
1,000
Chromium-51 
6,000
Cobalt-57 
1,000
Cobalt-58 
300
Cobalt-58m 
9,000
Cobalt-60 
100
Copper-64 
900
Dysprosium-165 
1,000
Dysprosium-166 
100
Erbium-169 
300
Erbium-171 
300
Europium-152 
200
Europium-154 
60
Europium-155 
600
Fluorine-18 
2,000
Gadolinium-153 
600
Gadolinium-159 
200
Gallium-72 
100
Germanium-71 
6,000
Gold-196 (196Au) 
600
Gold-198 (198Au) 
100
Gold-199 (199Au) 
600
Hafmium-181 
200
Holmium-166 
90
Hydrogen-3 (Tritium) 
20,000
Indium-113m 
3,000
Indium-114m 
60
Indium-115 
300
Indium-115 m 
1,000
Iodine-126 
3
Iodine-129 
1
Iodine-131 
3
Iodine-132 
90
Iodine-133 
10
Iodine-134 
100
Iodine-135 
30
Iridium-190 
600
Iridium-192 
100
Iridium-194 
90
Iron-55 
2,000
Iron-59 
200
Lanthanum-140 
60
Lead-203 
1,000
Lutetium-177 
300
Manganese-52 
90
Manganese-54 
300
Manganese-56 
300
Mercury-197 
900
Mercury-197m 
600
Mercury-203 
60
Molybdenum-99 
600
Neodymium-147 
200
Neodymium-149 
900
Neptunium-239 
300
Nickel-59 
300
Nickel-63 
50
Nickel-65 
300
Niobium-93m 
1,000
Niobium-95 
300
Niobium-97 
3,000
Osmium-185 
200
Osmium-191 
600
Osmium-191m 
9,000
Osmium-193 
200
Palladium-103 
900
Palladium-109 
300
Phosphorus-32 
30
Platinum-191 
300
Platinum-193 
3,000
Platinum-193m 
3,000
Platinum-197 
300
Platinum-197m 
3,000
Plutonium-241 
300
Potassium-42 
900
Praseodymium-142 
90
Praseodymium-143 
100
Promethium-147 
600
Promethium-149 
100
Protactinium-230 
600
Protactinium-233 
300
Rhenium-186 
300
Rhenium-187 
9,000
Rhenium-188 
200
Rhodium-103m 
30,000
Rhodium-105 
300
Rubidium-86 
600
Rubidium-87 
300
Ruthenium-97 
1,000
Ruthenium-103 
200
Ruthenium-105 
200
Ruthenium-106 
30
Samarium-151 
1,000
Samarium-153 
200
Scandium-46 
100
Scandium-47 
300
Scandium-48 
80
Selenium-75 
900
Silicon-31 
3,000
Silver-105 
300
Silver-110m 
90
Silver-111 
100
Sodium-22 
400
Sodium-24 
600
Strontium-85 
900
Strontium-85m 
20,000
Strontium-89 
20
Strontium-90 
8
Strontium-91 
200
Strontium-92 
200
Sulfur-35 (inorganic) 
500
Tantalum-182 
100
Technetium-96 
300
Technetium-96m 
30,000
Technetium-97 
6,000
Technetium-97m 
1,000
Technetium-99 
900
Technetium-99m 
20,000
Tellurium-125m 
600
Tellurium-127 
900
Tellurium-127m 
200
Tellurium-129 
2,000
Tellurium-129m 
90
Tellurium-131m 
200
Tellurium-132 
90
Terbium-160 
100
Thallium-200 
1,000
Thallium-201 
900
Thallium-202 
300
Thallium-204 
300
Thulium-170 
100
Thulium-171 
1,000
Tin-113 
300
Tin-125 
60
Tungsten-181 
1,000
Tungsten-185 
300
Tungsten-187 
200
Vanadium-48 
90
Ytterbium-175 
300
Yttrium-90 
60
Yttrium-91 
90
Yttrium-91m 
9,000
Yttrium-92 
200
Yttrium-93 
90
Zinc-65 
300
Zinc-69 
6,000
Zinc-69m 
200
Zirconium-93 
2,000
Zirconium-95 
200
Zirconium-97 
60
BOARD NOTE: This Table R derives from Table VI-2 (Annual Average Concentrations Yielding 4 Millirem per Year for a Two Liter Daily Intake), Statement of Basis and Purpose for the National Primary Drinking Water Regulations − Radionuclides, USEPA, Office of Radiation Protection (July 9, 1976), at 87-94, and Appendix I (Comparison of Derived Values of Beta and Photon Emitters), Implementation Guidance for Radionuclides, USEPA, Office of Ground Water and Drinking Water, EPA 816-F-00-002 (March 2002). USEPA based these values on NBS Handbook 69 (63), incorporated by reference in Section 611.102.
Calculating compliance with Section 611.330(d) under Section 611.742 requires dividing the measured concentration for each radionuclide by the appropriate conversion factor to determine its calculated fractional contribution to the total annual exposure limit of 4 mrem/yr:
The supplier then sums the fractional contributions for all radionuclides to determine the total fraction of the maximum exposure limit:
A sum of fractions result exceeding 1.00 exceeds the 4 mrem/yr standard in Section 611.330(d).
The total exposure is this sum of fractions (i.e., the total fraction of maximum exposure limit) times 4 mrem•yr‑1.
See Statement of Basis and Purpose for the National Primary Drinking Water Regulations − Radionuclides, USEPA, Office of Radiation Protection (July 9, 1976), at 80-86, and Implementation Guidance for Radionuclides, USEPA, Office of Ground Water and Drinking Water, EPA 816-F-00-002 (March 2002), pp. II-5 and II-6.
(Source: Added at 47 Ill. Reg. 16486, effective November 2, 2023)